The invention relates to liquid processing systems, and in particular to a system for endothermic processing of liquids and the precipitation of the dissolved substances from the liquid.
High-energy electrical discharge into a closed liquid volume for the purpose of changing chemical constituents or removing certain elements or compounds from solution has been known, sometimes under the name electro-hydraulics. U.S. Pat. No. 3,220,873 of R. H. Wesley, titled "Coating and Impregnation of Articles by Spark Generated Shock Waves" discusses the removal of constituents from liquids containing chemical compounds. Areas of application disclosed in the patent include plating of an electrode with metal, impregnation of surfaces with desired substances, and the removal of constituents from solutions as precipitates, such as for recovering metals from solution.
The following additional patents also have some relationship to the subject of electro-hydraulics: U.S. Pat. Nos. 3,222,902, 3,232,085, 3,267,710, 3,408,432, 3,456,291, 3,491,010, 3,609,286, 3,644,984, 3,688,535, 3,797,294, 3,857,265 and 4,077,888. These patents are not as pertinent to the subject matter of this invention as is the Wesley patent, most of them dealing with metal forming by electrical discharge.
Previous to the present invention, the use of high-energy electrical discharge into a volume of liquid had not been an efficient and practical tool for recovery of metals and other substances from liquids or slurries, for treatment of waste water, particularly with industrial wastes, for purification of water or other purposes. Previously nearly all work done with electro-hydraulics was experimental, not practical for industrial processes for several reasons. One reason was that in the repeated discharging of a high-energy electrical arc across a gap between electrodes, the electrodes are rather rapidly eroded and burned up. Similarly, switching components are consumed by burn-up. There has not been suggested any practical approach for addressing this problem, and such a substantial down time would have been required with previous systems, for replacing electrodes, insulators and switch elements consumed in the process, that the process was not made economically feasible.
Another problem with the systems suggested in prior patents was that the effect of the sharp shock wave that is sent through the liquid, on the firing chamber and auxiliary systems, was not taken into consideration.
Further problems with prior suggested systems were high self-inductance of electrical circuits and assemblies to the extent that efficiency would be severly reduced, high component cost, particularly replacement components, to the extent of diminishing feasibility, inefficient conduction of power to the electrodes in the firing chamber, and in general a failure to take advantage of the industrial potential of the process.
It is among the objects of the present invention to address these and other short comings of the prior systems, as well as to include further advantageous features which increase the efficiency of this process by a very large factor and make it applicable efficiently to a number of industrial processing applications and including new fields not previously contemplated.